Photocatalytic Reduction of Low-Concentration CO2: Progress and Challenges

Abstract

The photocatalytic resource utilization of low-concentration CO₂ (LC-CO₂) technology offers a green and environmentally friendly approach to addressing greenhouse gases in the environment. However, it currently faces several challenges, including inefficient selective adsorption of LC-CO₂ molecules at the interface leading to limited mass transfer, high activation energy barriers for LC-CO₂ on catalyst surface active sites, and low photon energy utilization and charge separation efficiencies. To address these challenges, this review provides a detailed exploration of the mechanisms for CO₂ adsorption/activation, reaction pathways, and photogenerated carrier dynamics, emphasizing the controlling role of the adsorption-activation step in the overall photocatalytic process. The design strategies such as enhancing CO₂ adsorption capacity, optimizing electronic and geometric structures, and modulating surface microenvironments are summarized. Recent studies demonstrate that constructing porous structures, surface functionalization, heterojunction engineering, facet engineering, defect engineering, and hydrophobic surface engineering can effectively enhance LC-CO₂ adsorption efficiency, improve the separation and migration efficiency of photogenerated carriers, and optimize reaction pathways, thereby significantly enhancing the efficiency and selectivity of photocatalytic LC-CO₂ reduction. Furthermore, interdisciplinary integration should be pursued, leveraging advanced scientific technologies such as machine learning and artificial intelligence to accelerate the discovery and optimization of novel materials and advance research to improve photocatalytic LC-CO₂ reduction research. The aim of this review is to provide relevant design insights for photocatalytic LC-CO₂ reduction research.